Gear-cutting machine.



T. PAWCUS. GEAR CUTTING MACHINE. APPLICATION FILED MAB. 11. 1911.

Patented Apr. 9, 1912.

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GEAR CUTTING MACHINE. APPL10AT10N FILED 11A11.11, 1911.

Patent-,d Apr. 9, 1912.

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T. PAWCUS.

. GEAR GUTTING MACHINE. A1 1 LI0ATI0H FILED MAR. 11.1911.

T. FAWGUS. GEAR CUTTING MACHINE. APPLIoA'rIoI FILED un. 11. 1911.

Patented Apr'. 9,11912. y 4 'SHEETS-SHEET 4.

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WITNESSES,

r (N Mam 'antan earns THQMAS FAWCU'S, OF PITTSBURGH, PENNSYLVANIA.

GEAR-CUTTING MACHINE.

Apiiicaaon aiedMarch 11, 1911.

To all whom it may concern Be it known that I, THoMAs Fawcr's, ofPittsburgh, Allegheny county, Pennsylvania, have invented a new anduseful Improvement in Gear-Cutting Machines, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings, forming part. of this specification, in which-Figure 1 is a plan view of a machine embodying my invention; Fig. 2 is aside elevation of the same; Fig. 3 is a transverse vertical sectionltaken on the line HIWIH of Fig. 1, and looking in the direction of thearrow; Fig. f1 is a side elevation of a portion Vof the machine,taken atthe opposite side from' Fig-2; Fig. is a sectional plan of a portion ofthe machine; and Figs. 6 and 7 are detail sectional views showing thedifferential gearing.

My invention has relation to gear cutting machines, andincre-particularly to a machine for cutting gears of the type commonlyknown as double-helical gears.

The object of my invention is to provide a machine of this character bymeans of which gears of this vtype may be accurately cut withcomparative rapidity.

My invention provides a machine having two cut-ting hobs arranged to actsimultaneously upon the gear blank, one hob cutting the portions of thedouble helical teeth at one side of the peripheral center of the blank,and the other hob cutting the teeth atv the opposite side of the center,together with means for feeding both hobs in the same direction whilecutting. It also provides means for a'ecting the cutters to cause themto produce cuts which areK at reverse angles to the axis of the blank inwhich the cuts are being made. It` also provides means for formingclearance spaces, whenA desired, at the apices of the teeth of thecharacter described and claimed in my Patent No. 971,980 of'October 4th,191-0. It also proxvides .a machine having certain novel operatingmechanisms.

Referring t the accompanying drawings, the numeral 2 designates the bedframe of the machine, which may be of any suitable character.

3 designates a rotary blank support-ing table, which is mounted torotate in a horizontal plane upon the vertical shaft 4, which is mountedin a carriage movable longi- Specicaton of Letters Patent.

Patented Apr. 9, 1912.

Serial No. 613,885.

tudinally on the hed of the machine on the ways 6.

l have shown as rigidly secured to the table 3 in any suitable manner,and which is to have double helical teeth cut thereon. I have indicatedat a and 7) the beginnings of the two sets of teeth. The teeth aextending from the upper edge ofthe blank to the center lin'e of theperiphery, are cut by a rotary hob 7, while the teeth@ which extend fromthe lower edge of the blank to the center, are cut by the hob 8. Thesetwo hobs are of ting teeth, which mesh with the teeth which. they cur inthe blanlnione ofthe hobs heilig right-handed and the other left-handed.The hob 7 is mounted upon a transverse shaft 9, while the hob 8.ismounted on a transverse shaft 10, t-heseftwo shafts being journaled oneabove another in `suitable bearings on a .vertically movable; slide orcarrier.11, which works on the vertical ways 12. Provision is also madeas indicated at 18,1whereby the bearings for the shaft 9 may be adjustedto vary the distance between the centers of the two shafts9-and 10 tosuit differentr 'sized gear blanks.

The slide or carrier 1.1 is given its feed movement by the verticalfeed'screwlll, which engages a. nut portion l5 ofthe yslide or carriage.end a worm wheel 1G, which is engaged and driven by a worm 17 on avertical shaft- 18 at one side of the machine. The hob shaft 10 has asimilar worm wheel'l9 at. the 0p worm 20 on the vertical shaftl.'

, .Each ot' the shafts 18 and 21 is formed in sections. as best shown inFig. 7, the t-Wo sections of each shaft being connected throng adifferential or planetary gear device, prsently'to be described, and thelower section of each shaft having bevel gear engagement 22 with atransverse driving shaft 23, this bearing beingso arranged that the twoshafts 18 and 2l are driven in opposite directions so that the two hobswill be. driven in the opposite directions indicated by the arrows on Fig. 2.

Any suitable form of differential or planetary gear may be employed forconlnecting the sectionsof the shafts18 and 21. 'In thc 'rh'awings, lhave shown a formv 0f this gearnin which the end of eachshaft secwellknown character, having helical cutf posite side of the machine drivenbya designates a partially cut blank, which The hob shaft 9 has at one and21 at the same rate of speed, the two differential gears at oppositesides of the machine being of. the same arrangement,

jes

and the gears 24 and pinions 25 transmitting the movement of the lowershaft sections to the upper shaft sections without changing the rate ofspeed. lVhen, however, thc shaft 29 is actuated to cause the worm wheels2S to rotate, the casings 26 will be rotated, and will thereby changethe' rate of rotation of the upper shaft sect-ions relatively to thelower shaft sections; and by reason of the fact that the two shafts 18and 2l are rotated in opposite directions, it will be seen that one ofthe hob shafts will be rotated at a relatively higher speed, while theother will be rotated at a relatively lower speed so long as the shaft29 is turning.

It is well known that in cutt-ing helical or spiral gears, in order toproduce teethof the proper angle nd pitch, there must, while the cutteris being fed across the face of the blank, be some provision made forrelat-ive movement of the blank carrier and' the cutter at a -speeddifferent from that which would be imparted, supposing either the blankor the cutter were rotated by its engagement with the other. y

It will be apparentthat inasmuch as the two hobs or cutters 7 and 8 areworking si-l multaneously upon the blank, and each forming one-half of adouble helical tooth, that the relative speeds of the two cutters withrespect to the blank must be varied, and that it is manifestlyimpossiblev to get the necessary variation by changing the speed of theblank relatively to the cutters,- since all portions of the blank mustrotate at the same speed. It is for this reason that the differentialgears above described are provided. These differential gears act todrive the hob or cutter 7 at a speed relatively slower than that of theblank and to drive the hob or cutter 3 at a speed relatively greaterthan that lofthe blank, or vice versa according to the direction ot' therotation of thc blank and cutters` whereby the proper angle and pitchof-tooth is produced. lnasmuch as the angle and-pitch of the teeth mayvary for different gears, provision is preferably made' for driving theworms 27'a't different spcedsf Various change gear mechanisms may beemployed for'this purpose. Various forms of gearing may also be providedfor driving the transverse shaft 23 and the feed screw 14. '.lhe

particular gearing which Il have illustrated,v

and which will now be described, will he understood to be illustrativeonly, and to` form no essential part of my invention.

30 (see Figs. 1 and 4) designate abelt pulley, which forms the maindrive of .the machine. The shaft of'this pulley carries the gear wheel31, which, through the gear 33, drives the shaft 23, and through the,

(See

worm 40, whichmeshes with a worm wheel A 41 on the table 3, these wormwheels providing means for the rotation of the table and gear blank. Theshaft 39 at one side of the machinealso carries a worm 42,'whieh' mesheswith a worm wheel 43 having attached thereto a gear wheel 44 on the stubshaft 45 which meshes with a gear Wheel 46.l The gear wheel 46 has anattached gear 47, which meshes with a gear 48 having an attached gear49, which in turn drives a pinion 50 on the worm shaft 29 beforereferred tof The gear 46 is mounted' on the trans verse shaft 51,carrying a bevel pinion 52, which meshes with a bevel pinion 54 on thelongitudinal shaft 55 having a threaded portion 56, which engages a nut57 on the carriage 5. The shaft 51 also has a bevel pinion 58 meshingwith a bevel pinion 59 on the feed shaft or screw 14 before referred to.Said shaft 51, through the shaft 55, forms the means for feeding theblank longitudinally of the machine, and also the driving shaft forfeeding the cutter or hob carrier. The two pinions 52 and 58 are looselymounted on the shaft 51, and are arranged to be alternately connectedtherewith by means of a sliding clutch hub 60, which is engaged by apivoted shifting arm 61. The gear 47 is Carried by a sleeve shaft 62,which is arranged to be clutched to the shaft 51 by the sliding clutchmember 63, engaged by a shifting lever 64. The'two shifting levers 61and 64 are connected by a link 65.

66 is an operating lever for the shifting levers.

67 is a shipping` rod having an adjustable collar 68, which is arrangedto be engaged by the carriage 5. This shipping rod also has theconnected member 67u provided with and 8 adjusted to abe cut in theblank. The lever 66 is now operated to throw the clutch member 60 intoengagement with the bevel pinion 52. The

shaft 56 is thus put into operation to feed 5 the blank'forwardly intocutting operation with the hobs, and this jis allowed to proceed untilthe required depth of cut is reached. The upper'hob 7 is set to cutslightly below the center line on the edge of the blank, and thehob 8 tocut approximately at the peripheral center of the blank. When the blankhas been fed, and the cutting operation has progressed until therequired dept-h of cut is reached, the carriage' 5 will strike'thecollar 68 and operate the shipping rod 67 connected to the lever G6 tothrow the clutch member 60 into the central position shown in F ig. 5. Afurther and more exact adjustment of the depth of cut 2o may be effectedby means of the hard wheel 71. The lever 66 is then moved by hand tothrow the clutch member 60 into engage' ment with the pinion 58, thus'setting in operation the vertical feed through the gear S9-and the screw14. At the same time the clutch vmember 63 is-thrown into engagementwith the clutch hub of the sleeve shaft 62, thereby vstarting the gear4'7 into action,

and through the gears 48 and 49 actuating the shaft 2,9carrying theworms 28, thereby causing the speed of the uppen portions of shafts 18and 21 to be varied, more or less, from the speed of the lower portionof said shafts, through the differential gearing 24, 25 and 26. It willbe seen that the gear 47 and the gears which are driven therefrom, A .upto and including Vthe planetary gears, do not become operative-until thefeed screw 1,4 'is 4set in motion, but that itis essential to theproduction of correctly formed y teeth that they-operate simultaneouslywith feed- `screw 14.

`It, will readily be understood that bythe use of change gears at asuitable point in the train of gearing described, that both the rate offeed of the feed screw 14, and also th'etilne relationl between thefeedand the differential gearing may be varied. Thus, in thearrangen'ient of gearing which I have shownby making the gear wheels 44and 46 change gears, the rate of feed of the shaft or screw 14 may bevaried; while by changing the gears 48 and 49, the time relation betweenthe feed and the differential gearing may be changed.

' In order'to enablerthe completion on the one machine of the doublehelical gears described and claimed in my patent above referred to', inwhich the meeting portions or apices of the connecting portions of thetwo sets of teeth are removed, I provide the machine with the attachmentnow to be described. On the shaft28 is a bevel gear wheel 72, 'whichmeshes with the bevel gear' 73 ou the longitudinal shaft 74. At itsopposite line Tend portion this shaft carries a bevelgear 75, meshingwith the bevel gear wheel 76 on a vertical shaft 77. The shaft 77carries a worm 7 8 meshing with the worm wheel 79 on a transverse cuttershaft 80provided 70- with a hob cutter 8l. said shaft being'incline'd soas to bring the teeth ofthe cutter 81 into a position to cut in a linesubstantially parallel to the axis ofthe blank. After the hobs orcutters 7A and 8 have com.- pleted their work, the gear 72 may be put inoperation toactuate the cutter 21 to thereby remove the apicesl of theconnecting portions of the two sets of teeth. The cutter shaft 80,together with its actuating gearing is mounted on the movable tail block82 which can be moved toward and away from the table 3 by any usualadjusting means. The bearings for the shaft 80 are carried,y by avertically movable block 83, having an 85 adjusting screw 84; and theworm 78 is vertically movable on its shaft 77 to suit the verticaladjustment given the shaft 80.

The machine described enables the teeth of. double helical gears ofvarying sizes' to 90 be accurately cut with comparative rapidity in theface of a solid blank, the two sets or portions of the teeth beingsimultaneously formed.

I do not wish to limit myself to the details of the machine as hereinshown and described, since I believe that I am the rst to provide amachine of this character having two hobs or cutters arranged to actsimultaneously upon the work and both feed-` ing in the same direction,preferably downward, or towardthe frame of the machine, as therebygreater solidity and hi-ghercutting speeds are obtainable.

fhile I refer t mount both of the cutters on a single slide or carrier,it will be obvious that this is not necessarily essential to myinvention, since the two hobs or cutters may bemounted in Various ways.I. also believe that it is broadly new to provide a machine having hobsor cutters working in the manner described with means fgr driving thetwo cutters at .relatively different speeds, the speed of one cutterbeing greater, while the speed of the other cutter is slower than thespeed ratio of the cutters and the gear being cut. It will be obviousthat machines embodyingthese essential features may differ widelyinconstruetion from the particular machine herein shown and described. 1

What I claim is 1 In a machine for cutting gears, a pair of rotaryli'obsI mounted on separate axes and arranged to act upon a continuouslyrevolving gear blank, and means' for feeding both hobs in the samedirection and' -in a arallel to the axis ofthe blankysubstantlally asdescribed. l A

2. In a machine for cutting gears, two"13 0 hobs revolving'in oppositedirections arranged toact upn a continuously revolving gear blank, andmeans for simultaneously feeding both hobs or critters in the samedirection; together with means for affecting said hobs to cause them toproduce cuts which are at reverse angles to their line of feed;substantially as described.

3. In a machine for cutting gears, a righthand and a left-hand hob,means for revolving said hobs in opposite directions, and means forfeeding them in the same direction, said hobs being arranged to actsimultaneously upon a continuously revolving gear blank; substantiallyas described.

4. In a machine for cutting double helical gears, the combination with ablank support, and means for continuously rotating said support, a toolcarrier having two simultaneously movable tools mounted thereon, one ofsaid tools being arranged to cut from one edge of a blank toward itscenter, and the other'tool to make a simultaneous cut from the centertoward. the opposite edge, and means for actuating the carrier andtools; substantially as described.

5. In a machine for forming double helicalA gears, two rotary cutters,means for feeding said cutters in the same direction, and means fordriving the cutters at relatively diiferent speeds; substant-ially asdescribed.

6. In a machine for forming helical gears, a rotary blank carrier, atool carrier movable in a direction parallel to the axis of the blank,and two cutters mounted on said carrier and arranged to actsimultaneously upon different portions of the blank; substantially asdescribed.

7. In a machine for forming helical gears,

a rotary blank carrier, a tool earriermovableV in a direction parallelto the axis of the blank, two cutters mounted -on Said carrier andarranged to act simultaneously upon different portions of the blank,together with means for varyingv the relative speeds of r0- tation ofthe two cutters A described.

8. In a machinefor forming double helical gears, a rotary blank carrier,a tool carrier, means for feeding said carrier ina line substantiallyparallel to the axis of the blank to be cut, a pair of cutters mountedon said carrier to move in unison therewith, and gearing for rotatingthe blank carrier and also for actuating the cutters, said gearinghaving means for rotating one of the cutters at a rate of speedrelatively slower than the speed ratio of the cutters and,gear being cutand for rotating the other cutter at a rate of speed relatively fasterthan the speed ratio of the cutters and gear being rut; substantially asdescribed.

9. In a machine for forming double helical gears, a rotary-blankcarrier, a cutter substantially asslide or carrier mounted for movementin a direction substantially parallel to the axis of the blank, twocutters mounted on said slide to move in unison therewith, gearing forfeeding said slide, and gearing for driving the cutters at differentrates of speed; substantially as described.

10. In a machine for forming double helical gears, a rotary blankcarrier, a cutter slide or carrier mounted for movement in a directionsubstantially parallel to the axis of the blank, two cutters mounted onsaid slide to move in unison therewith, gearing for feeding said slide,and gearing for drivingthe cutters at different rates of speed, togetherwith means for varying the feeding movement of the cutter slide;substantially as described.

11. In a machine for forming double helical gears, a rotary blankcarrier, a cutter slide or carrierl mounted for movement in a directionsubstantially parallel to the axis of the blank, two cutters mounted onsaid slide to move in unison therewith, gearing for feeding said slide,and gearing for driving the cutters at diiferent rates of speed, saidgearing having means for varying the relative speeds of the two cutters;substantially as described.

12. In a machine for forming double helical gears, a rotary blankcarrier, a cutter slide or carrier mounted for movement in a directionsubstantially parallel to the axis of the blank, two cutters mounted onsaid slide to move in unison therewith, gearing for feeding said slide,and gearing for driving the cutters-at different rates of speed, saidgearing having means for varying the feed of the slide and for changingthe gear relation between the said feed and the cutter driving gear;substantially as described.

13. In a machine for forming double helical gears, a rotary blankcarrier, gearing for actuating the same, a cutter slide, a pair ofcutters carried by said slide and arranged to feed in a linesubstantially parallel to the axis of the gear blank to be cut, meansfor varying the relative speeds ofthe two cutters, and means for movingthe blank c arrier toward and away from the cutter slide; substantiallyas described.

14. In a machine for forming double helical gears, a blank carrier, apair of cutters arranged to' act upon different portions of the blank,means for feeding bo'th of said cutters in the same direction in alinesubstantially parallel to the axis of the blank, and another cutterarranged to act upon portions of the teeth formed by the'said cutvters;substantially as described.

l5. In a machine for Acutting gears, twoy rotary cutters, means forfeeding said cutters in the same direction, a blank support, and meansfor veffecting a relative feeding movement ot' the support and cuttersin a direction substantially perpendicular to the first-named feedtogether With means for affecting said cutters to cause them-to producecut-s which are at reverse angles to their line of feed; substantiallyas described.

16. In a machine for forming double helical gears, two hobs, means forfeeding said hobs in the same direction7 and means for 'affecting saidhobs to cause them to produce cuts which are at reverse angles toxtheir. line 10 -of feed; substantially as described.

In testimony whereof, I havehereunto set my hand.

, Trios. FAWCUS.

Witnesses H. M. CORWIN, Gmo. H; PiiRMELEE.

